"...The floor of the crater as a lot of rilles, and a close look at that crater floor reveals to me a lot of possible sky light entrances, more than indicated by the images at the llink. (Go here, click on projections and pick “Orthographic (North Pole).” Then zoom in on the crater indicated by the yellow X in my image on the right above.)

The key here is that caves or lava tubes provide a good place to cheaply and quickly establish a lunar colony. While it is suspected that water might survive in permanently shadowed regions near the poles, up until now no one had found any good underground locations there. If this suspected skylight entrances prove true, this crater then becomes prime real estate on the Moon...."

Philolaus Crater is additionally appealing due to its relatively young age, which would allow studies of the Moon’s more recent evolution. It is one of few large craters formed during the Copernican Era, that is, within the last 1.1 billion years or so of lunar history. Also, being on the near side, Philolaus affords direct communications with the Earth.

“We would also have a beautiful view of Earth. The Apollo landing sites were all near the Moon’s equator, such that the Earth was almost directly overhead for the astronauts. But from the Philolaus skylights, Earth would loom just over the crater’s mountainous rim, near the horizon to the southeast” adds Lee.

“Our next step should be further exploration, to verify whether these pits are truly lava tube skylights, and if they are, whether the lava tubes actually contain ice. This is an exciting possibility that a new generation of caving astronauts or robotic spelunkers could help address” says Lee. “Exploring lava tubes on the Moon will also prepare us for the exploration of lava tubes on Mars. There, we will face the prospect of expanding our search for life into the deeper underground of Mars where we might find environments that are warmer, wetter, and more sheltered than at the surface.”